//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 10325 SUBJECT: GRB 100115A detected in ground analysis of Swift-BAT data DATE: 10/01/15 22:11:11 GMT FROM: Jay R. Cummings at NASA/GSFC/Swift J. R. Cummings (NASA/GSFC/UMBC), N. Gehrels (NASA/GSFC), H. A. Krimm (NASA/GSFC/USRA), D. M. Palmer (LANL) report on behalf of the Swift Team: At 11:15:19UT, BAT detected GRB 100115A during a preplanned Swift slew maneuver. A source was found in ground analysis of event data collected for the BAT Slew Survey at RA, Dec 3.333, -0.817, which is RA (J2000) 00 13 19.9 Dec (J2000) -00 49 01 with an estimated 90% containment uncertainty of 4 arcmin radius. The burst was a single FRED pulse with a T90 of about 3 seconds. There was no detectable flux above 100 keV. A Swift TOO has been approved. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 10326 SUBJECT: GRB 100115A: Swift-XRT candidate afterglow DATE: 10/01/16 10:59:04 GMT FROM: Raffaella Margutti at U. di Milano Bicocca R. Margutti (INAF-OAB), B. Sbarufatti (OAB), J. R. Cummings (NASA/GSFC/UMBC), M. De Pasquale (MSSL/UCL) report on behalf of the Swift-XRT team: Swift began observing the field of the Swift BAT Slew Survey (BATSS) GRB 100115A (Cummings et al. GCN Circ. 10325) 40ks after the trigger. Using 2.5 ks of XRT Photon Counting mode data we detect a single X-ray source source inside the BAT error circle at RA, DEC= 3.3664, -0.8263 which is equivalent to: RA (J2000): 00h 13m 27.93s Dec (J2000): -00d 49' 34.8" with an uncertainty of 6.8 arcsec (radius, 90% confidence). The source is detected at a level of 6.6x10^-3 count sec^-1. Given the current statistics it is not possible to determine whether this source is fading. A tentative spectrum formed from the PC mode data can be fitted with an absorbed power-law with a photon spectral index of 2.7 (+1.7, -0.8). The best-fitting absorption column is consistent with the Galactic value of 3.1 x 10^20 cm-2 (Kalberla et al. 2005). The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 2.9 x 10^-11 (3.6 x 10^-11) erg cm^-2 count^-1. The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00020126. This circular is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 10327 SUBJECT: GRB 100115A: Swift/UVOT Upper Limits DATE: 10/01/16 13:07:40 GMT FROM: Patricia Schady at MSSL/Swift S. R. Oates (MSSL-UCL) reports on behalf of the Swift/UVOT team: The Swift/UVOT began observerving the field of Swift BAT Slew Survey (BATSS) GRB 100115A (Cummings et al. GCN Circ. 10325) 40ks after the BAT trigger. We do not detect any source at the candidate Swift XRT position (Margutti et al. GCN Circ. 10326). The 3 sigma upper limits for the summed images are reported below: Filter T_start(s) T_stop(s) Exposure Mag(3 sgma UL) ########################################################### b 40636 46609 411 >20.19 u 40423 46395 411 >19.85 uvw1 40001 46180 824 >20.29 uvw2 40849 47260 1098 >20.99 ########################################################### The above magnitudes are not corrected for the Galactic extinction corresponding to a reddening of E_{B-V} = 0.06 mag (Schlegel et al., 1998, ApJS, 500, 525). The photometry is on the UVOT photometric system described in Poole et al. (2008, MNRAS, 383,627). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 10328 SUBJECT: GRB 100115A: SARA Afterglow Candidate DATE: 10/01/16 21:28:38 GMT FROM: Adria C. Updike at Clemson U Adria C. Updike, Dieter H. Hartmann (Clemson University) and Robert Berrington (Ball State University) report: We observed the field of the Swift-detected GRB 100115A (Cummings et al., GCN 10325) with the 0.9m SARA telescope located at Kitt Peak National Observatory beginning 15 hours and 20 minutes after the BAT detection under good conditions. In a single 1200 sec exposure, we detect a source within the XRT error circle (Margutti et al., GCN 10326) around R ~ 22 mag (as compared to USNO B.1 catalog field stars). There is no corresponding counterpart in either SDSS or Sloan. The Sloan survey goes deeper than our image, indicating the new source in the XRT error circle is a potential candidate for the afterglow of GRB 100115A. No statement about variability can be made at this time; further observations are encouraged. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 10329 SUBJECT: NOT observation of GRB100115A localization DATE: 10/01/17 01:27:15 GMT FROM: Martin Jelinek at Inst.Astrophys.Andalucia,Granada Martin Jelinek (IAA CSIC Granada), Petr Kubanek (IPL Valencia) and Javier Gorosabel, Antonio J. Delgado (IAA CSIC) on behalf of a larger colaboration. report: We observed the Swift-XRT errorbox of the GRB100115A (Margutti et al. GCN 10326) with the 2.56 Nordic Optical Telescope at La Palma. We acquired 7x 300s i' band exposure at about 32 hours after the GRB. The detection limit of this image is about i' = 24.0 mag. We detect four sources within or at the border of the X-ray errorbox. None of these objects is present in the SDSS DR7 image, with the exception of A, which could be believed to be at the its very detection limit. This object also seems in our image extended and/or composed of two components. Given the lack of astrometric information in the Updike et al. (GCN 10328) we cannot confirm or decide whether one of these objects is an optical afterglow of GRB100115A. We however do not see any object as bright as previously reported, which might confirm the decaying behaviour of the afterglow candidate by SARA. The identification card with the objects marked A, B and C can be downloaded from http://www.iaa.es/mates/grb100115a-not-errorbox.jpg This message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 10331 SUBJECT: GRB100115A: Revision of NOT observation DATE: 10/01/17 03:10:10 GMT FROM: Martin Jelinek at Inst.Astrophys.Andalucia,Granada Martin Jelinek (IAA CSIC Granada), Petr Kubanek (IPL Valencia) and Javier Gorosabel, Antonio J. Delgado (IAA CSIC) on behalf of a larger colaboration. report: In light of the new XRT improved position we reexamined the NOT image from our previous report (Jelinek et al., GCN 10329) and found that only the (extended) object A at 00:13:28.12 -00:49:32.6 +-2" (J2000) stays within the XRT errorbox and may be possibly related to the GRB100115A, either as its afterglow, host galaxy or a combination of both. The improved identification card can be downloaded from http://www.iaa.es/~mates/grb100115a-not-errorbox2.jpg We thank Alex Kann for pointing out the new XRT position. This message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 10332 SUBJECT: GRB 100115A: SARA Astrometry DATE: 10/01/17 04:56:47 GMT FROM: Alexander Kann at TLS Tautenburg D. Alexander Kann (TLS Tautenburg), Adria C. Updike and Dieter H. Hartmann (Clemson University) report: We performed astrometry (against the USNO-B1.0 catalog) on the image of the field of GRB 100115A (Cummings et al., GCN 10325) taken by the 0.9m SARA observatory at KPNO, which revealed a possible afterglow candidate (Updike et al., GCN 10328). For this object, we derive a position of (conservative error 1"): RA (J2000): 00:13:28.05 Dec. (J2000): -00:49:32.4 in full agreement with the position given for Object "A" by Jelinek et al. (GCN 10331), and possibly closer to (or identical with) the brighter southwest component of Object "A". Given the lack of photometric information in Jelinek et al. (GCN 10331) we cannot confirm if the SARA candidate has faded significantly, but note that, in the SARA image, the afterglow candidate is about as bright as the star to the southwest at RA (J2000): 00:13:27.20, Dec. (J2000): -00:49:42.4, and it seems to be much fainter than this source (note the different filters, though) in the Jelinek finding chart. This message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 10334 SUBJECT: GRB 100115A: Enhanced Swift-XRT position DATE: 10/01/17 10:18:01 GMT FROM: Raffaella Margutti at U. di Milano Bicocca R. Margutti (INAF-OAB), P.A. Evans and M.R. Goad (U. Leicester) report on behalf of the Swift-XRT team: Using 1321 s of XRT Photon Counting mode data and 1 UVOT images, we find an astrometrically corrected X-ray position (using the XRT-UVOT alignment and matching UVOT field sources to the USNO-B1 catalogue): RA, Dec =3.36730, -0.82650 which is equivalent to: RA (J2000): 00 13 28.16 Dec (J2000): -00 49 35.4 with an uncertainty of 4.0 arcsec (radius, 90% confidence). This position may be improved as more data are received. The latest position can be viewed at http://www.swift.ac.uk/xrt_positions. Position enhancement is described by Goad et al. (2007, A&A, 476, 1401) and Evans et al. (2009, MNRAS, 397, 1177). This circular is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 10335 SUBJECT: GRB 100115A: Gemini-N photometry DATE: 10/01/17 16:53:52 GMT FROM: Antonino Cucchiara at PSU A. Cucchiara, D. B. Fox (PennState), E. Berger (Harvard U.) report on behalf of a larger collaboration: "On January 16.20 UT we observed the field of GRB100115A (Cummings et al. 10325, Margutti et al. GCN 10326) with the Gemini-North GMOS camera in r and g bands. We collected a sequence of 5x180s images in each filter. In the coadded images the afterglow candidate is visible in both filters (GCN 10328,10331,10332). On January 17.20 UT we collected a second epoch with the same set-up. The following magnitude have been calibrated using the USNO-B1.0 star at RA: 00:13:30.44 Dec: -00:49:16.93 ( = 19.76 mag): Jan. 16.20 UT: r = 21.37 +- 0.08 mag Jan 17.20 UT: r = 21.86 +- 0.08 mag A similar fading of ~0.5 mag is present in our g-band observations. Therefore we conclude that Object "A", which shows two structures, contains a fading transient. Further observation are planned. We thank the Gemini staff, in particular Sandy Leggtt, for performing these observations. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 10352 SUBJECT: GRB 100115A: Swift-XRT refined analysis DATE: 10/01/20 08:55:01 GMT FROM: Raffaella Margutti at U. di Milano Bicocca R. Margutti, B. Sbarufatti (INAF-OAB), S. Oates (MSSL/UCL), report on behalf of the Swift-XRT team: The Swift ToO observations of the BATSS burst GRB 100115A (Cummings et al., GCN Circ. 10325) started 40ks after the trigger. The XRT data set consists of 8 ks exposure in PC mode split into two epochs: the first observation was performed at T0+40 ks, while a second epoch of observations was acquired at T0+306 ks. The UVOT-enhanced XRT position was given by Margutti et al. in GCN Circ. 10334. In the second observation the X-ray source reported by Margutti et al., GCN Circ.10326 has faded to a level of (1.4 +/- 0.9)e-3 count/sec corresponding to a decay index of -0.7 +/- 0.4. This source is likely to be the afterglow of GRB 100115A. No further observations are planned. A spectrum formed from the PC mode data can be fitted with an absorbed power-law with a photon spectral index of 2.0 (+1.0, -0.5). The best-fitting absorption column is consistent with the Galactic value of 3.1 x 10^20 cm^-2 (Kalberla et al. 2005). The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 3.4 x 10^-11 (3.8 x 10^-11) erg cm^-2 count^-1. The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00020126. This circular is an official product of the Swift-XRT team.